Connector for flexible printed circuit board

ABSTRACT

An FPC connector having an electromagnetic wave shielding structure improved so that noises do not exceed an allowable value. The FPC connector includes at least a top plate, a metallic shell having left and right walls and a grounding terminal portion, a connector body covered with the metallic shell, a signal line contact, and a grounding contact for grounding the FPC, wherein the metallic shell has a grounding contact partially cut from the top plate and raised the cut portion.

This application claims priority from Japanese Patent Application Nos.2003-346284 filed Oct. 3, 2003 and 2004-239954 filed Aug. 19, 2004,which are incorporated hereinto by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a connector for a flexible printedcircuit board for mutually connecting electronic components inelectronic apparatuses (hereinafter referred to as an FPC connector),more specifically, to the FPC connector improved for forming a groundcontact in the FPC connector for avoiding the interfere ofelectromagnetic waves with the flexible printed circuit (hereinafterreferred to as an FPC).

2. Description of the Related Art

Up to now, in the FPC connector, part or all of the connector is coveredwith a metallic shell and the metallic shell and FPC are grounded forshielding the FPC connector from the electromagnetic field as well assuppressing the generation of noise in a signal line or grounding thegenerated noise as much as possible (see Japanese Patent No. 3425696).

A typical conventional shield structure is illustrated in FIG. 7 whichis an enlarged sectional view of a portion thereof for grounding the FPCwhen the FPC is inserted into a FPC connector.

The FPC connector 101 generally includes a metallic shell 102, aconnector body 103, a pair of grounding contacts 104 and a plurality ofsignal line contacts 105.

The metallic shell 102 functions as a shield for electromagnetic wavesand covers at least upper and left/right sides of the connector body 103so that it is suitably grounded via the left/right sides to anelectronic apparatus to which the FPC connector 101 is attached. Theconnector body 103 is made of insulating resin and formed as arectangular tube having an outer shape of substantially aparallelepiped, through which a space 103 a extends forward/rearward.The grounding contacts 104 is press-fit and fixed into grooves 103 dformed in a bottom wall 103 c constituting the space 103 a of theconnector body 103 in correspondence to a grounding pads (not shown) inFPC 110 inserted therein. As shown in FIG. 7, the grounding contact 104is of a generally U-shape and has a contact portion 104 a to be incontact with the grounding pad of the FPC 110, a grounding portion 104 bat the other end, and a fixing portion 104 c to be press-fit into thegroove 103 d in a middle region thereof. The grounding portion 104 b isgrounded the electronic apparatus to which the FPC connector isattached. The signal line contact 105 includes a contact portion to bein contact with the pad of the FPC 110, a fixing portion to be fixed tothe connector body 103 and a terminal portion 105 a to be connected to acircuit of the electronic apparatus (see Japanese Patent No. 3425696 orothers).

As shown in FIG. 7, when the FPC 110 is guided along an inside surfaceof an upper wall 103 b of the FPC connector 101 and inserted into thespace 103 a, the grounding contact 104 and the signal line contact 105fixed to the bottom wall 103 c are brought into contact with thecorresponding pad of the FPC 110 from the lower side; i.e., from thebottom wall side.

The conventional FPC connector reduces the interference fromelectromagnetic waves by the above-mentioned electromagnetic waveshielding structure. However, in the conventional FPC connector, sincethe grounding contact 104 of the FPC is fixed to the bottom wall 103 cof the connector body 103 and brought into contact with the FPC 110 fromunderside, the manufacturing error of the depth of the groove 103 d andthe grounding contact 104 itself is generated. Therefore, it isimpossible to always maintain a gap between the contact portion 104 a ofthe grounding contact 104 and the inside surface of the upper wall 103 bof the connector body 103 at a constant value. This may result in theadverse contact between the grounding contact 104 and the FPC, whichimpedes the stable contact. As a result, there is a risk of increasingnoises, far from reducing them.

FIG. 8 is a graph of the measurement of the radiated disturbance of theconventional FPC connector (the electromagnetic disturbance wherein theenergy thereof is propagated through a space as electromagnetic waves).As shown in FIG. 8, it is apparent that noises having the field strengthexceeding the allowable value (the limit line shown by a solid line inthe graph) generate in the signal line even in the above-mentionedelectromagnetic wave shielding structure.

The present invention has been made in view of such a problem, and anobject thereof is to provide an FPC connector having an electromagneticwave shielding structure improved so that noises are prevented fromexceeding the allowable value.

SUMMARY OF THE INVENTION

To achieve the above-mentioned object, the FPC connector in accordancewith the present invention comprises at least a top plate, a metallicshell having left and right walls and a grounding terminal portion, aconnector body covered with the metallic shell, a signal line contact,and a grounding contact for grounding the flexible circuit board,wherein the metallic shell has a grounding contact partially cut fromthe top plate and raised the cut portion.

The metallic shell preferably further comprises a fixing piece to bepress-fit in the connector body, formed by partially cutting from thetop plate and bending the cut portion in parallel to the side wall ofthe metallic shell.

The metallic shell preferably further comprises an FPC-fixing/removingspring piece formed by partially cutting from the top plate and raisingthe cut portion, and the FPC-fixing/removing member is held by thespring piece.

According to the FPC connector of the present invention, it is possibleto reduce the manufacturing error in comparison with the prior artwherein the grounding contact is formed as a separate member andattached to the connector body, whereby the electric contact of the FPCwith the grounding contacts is further ensured. As a result, it ispossible to prevent noises from exceeding the allowable value. Also,since the grounding contact is formed integral with the metallic shell,it is possible to decrease the number of parts and simplify theproduction process, whereby the production cost is saved.

By press-fitting the metallic shell into the contact body from the rearside thereof with the fixing piece, it is possible to easily positionthe grounding contact.

Further, by partially cutting the spring piece for theFPC-fixing/removing mechanism from the metallic shell and raising thecut portion, it is possible to reduce the production steps and therebyto save the production cost.

Also, by providing the FPC-fixing/removing mechanism, the inserted FPCdoes not fall off from the FPC connector.

The above and other objects, effects, features and advantages of thepresent invention will become more apparent from the followingdescription of embodiments thereof taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is an upper plan view of the FPC connector in accordance withthe present invention;

FIG. 1B is a perspective view of the FPC connector in accordance withthe present invention;

FIG. 2 is a perspective view of a metallic shell of the FPC connector;

FIG. 3A is a sectional view of the FPC connector taken along a line A-Awhen the FPC is not inserted;

FIG. 3B is a sectional view of the FPC connector taken along a line B-Bwhen the FPC is not inserted;

FIG. 4A is a sectional view of the FPC connector corresponding to FIG.3A when the FPC is inserted;

FIG. 4B is a sectional view of the FPC connector corresponding to FIG.3B when the FPC is inserted;

FIG. 5 is a schematic plan view of a stopper member 7 constituting anFPC-fixing/removing mechanism;

FIG. 6A is a sectional view taken along a line C-C in FIG. 1A when theFPC is not inserted;

FIG. 6B is a sectional view taken along a line C-C in FIG. 1A when theFPC is inserted;

FIG. 6C is a sectional view taken along a line C-C in FIG. 1Aillustrating a state of the FPC-fixing/removing mechanism after the FPChas been inserted;

FIG. 7 is an sectional view of a portion for grounding FPC when the FPCis inserted into the conventional FPC connector; and

FIG. 8 is a graph illustrating the field strength of noises generated inthe conventional FPC connector by the radiated disturbance.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The preferred embodiments of the present invention will be describedbelow with reference to FIGS. 1A to 4B.

FIGS. 1A and 1B illustrate the FPC connector in accordance with thepresent invention, wherein FIG. 1A is an upper view thereof; FIG. 1B isa perspective view thereof; FIG. 2 is a perspective view of a metallicshell of the FPC connector; FIGS. 3A and 3B are sectional views of theFPC connector when the FPC is not inserted, more specifically FIG. 3A isa sectional view taken along a line A-A in FIG. 1A and FIG. 3B is asectional view taken along a line B-B in FIG. 1A; and FIGS. 4A and 4Bare sectional views of the FPC connector similar to FIGS. 3A and 3B whenthe FPC is inserted, more specifically FIG. 4A is a sectional view takenalong a line A-A in FIG. 1A and FIG. 3B is a sectional view taken alonga line B-B in FIG. 1A.

As shown in FIGS. 1A and 1B, the FPC connector in accordance with thepresent invention generally includes a metallic shell 2, a connectorbody 3 and a plurality of signal line contacts 5.

The metallic shell 2 functions for shielding electromagnetic waves in asimilar manner as in the prior art. The metallic shell 2 includes a topplate 21 for covering at least an upper portion of the connector body 3,and side walls 22 a, 22 b for covering left and right portions of theconnector body 3. The metallic shell 2 is suitably grounded viagrounding terminal portions 23 a, 23 b provided at lower ends of theleft and right side walls 22 a, 22 b, respectively, to an electronicapparatus to which the FPC connector 1 is attached.

According to the present invention, as clearly shown in FIG. 2, a pairof grounding contacts 24 a, 24 b is formed integral with the metallicshell 2 in correspondence to grounding pads of the FPC 10. Each of thegrounding contacts 24 a, 24 b is formed, for example, by partiallypress-cutting from the top plate 21 of the metallic shell 2 and raisingthe cut portion to be a piece having a predetermined shape extendingdownward from the top plate in the vertical direction, which piece isthen bent to have a generally L-shape with a C-shaped free end. In thisproduction process, the pair of grounding contacts 24 a, 24 b having theFPC contact portions 24 a 1, 24 b 1, which are elastically deformablefree ends, are formed at the same time.

By forming the pair of grounding contacts 24 a, 24 b in such a mannerand sandwiching the FPC 10 between the top plate 21 of the metallicshell 2 and the grounding contacts 24 a, 24 b along an upper wall 32 ofthe connector body 3 (see FIG. 4B), it is possible to reduce themanufacturing error in comparison with the prior art wherein thegrounding contact is formed as a separate member and attached to theconnector body 3, whereby the electric contact of the FPC with thegrounding contacts 24 a, 24 b is further ensured. Also, since thegrounding contacts 24 a, 24 b are formed integral with the metallicshell 2, it is possible to decrease the number of parts and simplify themanufacturing process as well as save the production cost.

In this regard, in FIG. 2, reference numerals 25 a, 25 b denote a pairof spring pieces for facilitating the attachment/detachment of the FPC10 relative to the connector 1 described later, which constitutes aFPC-fixing/removing mechanism. The pair of spring pieces 25 a, 25 b isdisposed outside the pair of grounding contacts 24 a, 24 b, and ispartially cut from the top plate 21 of the metallic shell 2 and raisedthe cut portion in a similar manner as the pair of grounding contacts 24a, 24 b. Also, reference numerals 26 a, 26 b denote a pair of fixingpieces for fixing the metallic shell 2 to the connector body 3, which ispartially cut from the top plate 21 and bent the cut portion in parallelto the side walls 22 a, 22 b, respectively, in a rear area (an upperarea in FIG. 1A) of the metallic shell 2. The pair of spring pieces 25a, 25 b and the pair of fixing pieces 26 a, 26 b may be formed at thesame time in the process for forming the grounding contacts 24 a, 24 b.

The contact body 3 is made of insulating resin to have an outer shape ofa generally parallelepiped and formed as a rectangular tube, throughwhich a space 31 extends forward/rearward of the connector body 3 (theupward/downward direction in FIG. 1A). In the space 31, the FPC 10 canbe inserted. The connector body 3 is provided with a stopper member 7constituting a fixing/removing mechanism for facilitating theattachment/detachment of the FPC in front of the upper wall 32 definingthe upper limit of the space 31 (in a lower area in FIG. 1A), and apositioning projection 6 for attaching the connector body to theelectronic apparatus at a predetermined position in a lower area of alower wall 33 defining a lower limit of the space 31 (see FIGS. 3A and3B).

The fixing piece 26 of the metallic shell 2 and bases 52 of the signalline contacts 5 described later are press-fit into holes formedrespectively in the connector body 3 in correspondence thereto from arear side of the connector body 3 (from the upper side in FIG. 1A andthe right side in FIGS. 3A to 4B), whereby the metallic shell 2 and thesignal line contacts 5 are fixed to the connector body 3. Simultaneouslytherewith, the pair of grounding contacts 24, 24 and the signal linecontacts 5 are correctly located in the interior of the space 31 of thecontact body 3.

As shown in FIGS. 3A and 4A, the signal line contact 5 includes amovable contact portion 51 brought into contact with a signal line padof the FPC corresponding thereto, a base 52 press-fit into a hole or aslit 34 formed in the connector body 3, a terminal portion 54 as asoldering portion being electrically connected to an electrode pad ofthe circuit board in the electronic apparatus, and a coupling portion 53for coupling the movable contact portion 51 and the base 52 with theterminal portion 54. As clearly shown in FIG. 4A, the signal linecontact 5 is formed to sandwich the FPC 10 between the base 52 and themovable contact portion 51 via the upper wall 32 of the connector body3.

Next, the FPC-fixing/removing mechanism for facilitating theattachment/detachment of the FPC will be described with reference toFIG. 5. FIG. 5 is a schematic plan view of the stopper member 7constituting the FPC-fixing/removing mechanism wherein the FPC 10 isinserted.

The stopper member 7 includes a push button 71 located in a generallymiddle portion thereof, a pair of arm members 72 a, 72 b extendingleftward and rightward from the push button 71, a pair of projections 73a, 73 b extending rearward from front ends which are free ends of thearm members 72 a, 72 b generally in the vertical direction thereto, anda pair of engagement members 74 a, 74 b extending inward (to a center)from front ends of the projections 73 a, 73 b generally in the verticaldirection thereto. The front ends of the pair of arm members 72 a, 72 bare elastically held by the pair of spring pieces 25 a, 25 b partiallycut from the top plate 21 of the metallic shell 2 and raised the cutportion to be located on the lower side (the back side of the paper inFIG. 5) (see FIG. 6A). Also, the pair of engagement members 74 a, 74 bis projected inward from the projections 73 a, 73 b to be located on apassage of the FPC 10 inserted into the space 31. Accordingly, they areengageable with a pair of recesses 12 a, 12 b formed on both sides ofthe front end of the FPC 10 inserted.

The operation of the FPC-fixing/removing mechanism of theabove-mentioned structure will be described with reference to FIGS. 6Ato 6C. FIGS. 6A to 6C are the C-C cross-section in FIG. 1A andillustrate the operation of the spring piece and the stopper memberconstituting the FPC-fixing/removing mechanism.

As shown in FIG. 6A, when the FPC 10 is absent, the stopper member 7,more accurately the arm members 72 a, 72 b are pushed upward by thecorresponding spring pieces 25 a, 25 b.

In FIG. 6B, when the FPC 10 is inserted into the FPC connector 1, thepush button 71 of the stopper member 7 is pushed down by a finger orothers. Then, the arm members 72 a, 72 b formed in integral with thepush button 71 are also pushed down against the elastic force of thespring pieces 25 a, 25 b. Thereby, the projections 73 a, 73 b and theengagement members 74 a, 74 b formed in integral with the arm members 72a, 72 b are also pushed down.

When the engagement members 74 a, 74 b are pushed down to get out of thepassage of the FPC 10, the FPC 10 can be inserted to a predeterminedposition in the space 31. When the pressure applied to the push button71 is released after the FPC 10 has completely been inserted, thestopper member 7 including the arm members 72 a, 72 b returns to theoriginal position (see FIG. 6C). Accordingly, the engagement members 74a, 74 b also return to the passage of the FPC 10 in the space 31.

At this time, if the FPC 10 is inserted to the predetermined position,the engagement members 74 a, 74 b are fit into the recesses 12 a, 12 b.Thereby, the FPC 10 is electrically brought into contact with the signalline contacts 5 and the grounding contacts 24 a, 24 b, and assuredly fitto the FPC connector 1 without falling off therefrom.

When the FPC 10 is detached from the FPC connector 1, the push button 71of the stopper member 7 is pushed down in a similar manner as shown inFIG. 6B to detach the engagement members 74 a, 74 b from thecorresponding recesses 12 a, 12 b of the FPC 10. Thereby, the FPC 10 isremovable from the connector 1.

Since the FPC connector 1 in accordance with the present invention isstructured as described above, if the FPC is inserted into the space 31from the front side of the connector body 3, the respective pads of theFPC 10 are electrically connected to the respective signal line contacts5 corresponding thereto while being sandwiched between the upper wall 32of the connector body 3 and the signal line contacts 5 or the groundingcontacts 24 as shown in FIGS. 4A and 4B, and the FPC 10 is assuredlyheld in the connector 1 by the action of the FPC-fixing/removingmechanism, whereby the FPC 10 does not fall off from the connector 1during the use. In this regard, reference numeral 11 shown in FIGS. 4Aand 4B denotes a spacer of insulating resin attached to the back side ofthe FPC (opposite to a side on which the pads are formed), which is notindispensable but preferably provided for ensuring theattachment/detachment of the FPC relative to the connector or increasingthe contact pressure of the pads in the FPC and the respective contacts.

The present invention has been described in detail with respect topreferred embodiments, and it will now be apparent from the foregoing tothose skilled in the art that changes and modifications may be madewithout departing from the invention in its broader aspect, and it isthe intention, therefore, in the apparent claims to cover all suchchanges and modifications as fall within the true spirit of theinvention.

1. A connector for a flexible printed circuit board comprising at leasta top plate, a metallic shell having left and right walls and agrounding terminal portion, a connector body covered with the metallicshell, a signal line contact, and a grounding contact for grounding theflexible printed circuit, wherein the metallic shell has the groundingcontact partially cut from the top plate and raised the cut portion. 2.A connector for a flexible circuit board as claimed in claim 1, whereinthe metallic shell further comprises a fixing piece to be press-fit inthe connector body, formed by partially cutting from the top plate andbending the cut portion in parallel to the side wall of the metallicshell.
 3. A connector for a flexible circuit board as claimed in claim1, wherein the metallic shell further comprises a spring piece for anFPC-fixing/removing mechanism formed by partially cutting from the topplate and raising the cut portion.
 4. A connector for a flexible circuitboard as claimed in claim 3, wherein a stopper member for theFPC-fixing/removing mechanism is held by the spring piece.